1. Field of the Invention
The present invention relates to an oil cooler adapted to be attached or applied to, for example, an engine housing of cars and motor cycles from the outside, and in particular to an oil cooler provided with few places of sealed portions between a motor oil passage and a cooling water passage, so that mixturing chance of the motor oil and the cooling water is considerably reduced, which cooler being of a simple construction and compact, and a manufacturing method for the oil cooler above.
2. Description of the Prior Art
In general, the engine rooms of cars and motor cycles and the like machines have been lubricated and cooled by using engine or motor oil. An engine block of the engine housing has an inlet port of the lubricant passage to which inlet port an oil cooler is seated through an O-ring. Such oil cooler is described in U.S. Pat. No. 3743011. According to the prior art described in the U.S. Patent, the oil cooler has a plurality of elements of a shape of flat doughnut through which elements motor oil circulates and around which elements cooling water circulate. The oil once enters an oil filter through a bypass formed in the core of the oil cooler, then flows from the oil cooler casing to the cooler elements. According to the conventional oil cooler above, the core element is fabricated by a pair of metal sheets provided with relatively many holes formed through the metal sheets. In consequence, the oil passage becomes considerably complicated, the area of the metal sheets to be sealed or of water-tight increases, making the production of the core elements complicate and difficult, and the number of parts increases.
Some oil coolers have been produced from aluminum so as to reduce the weight. Such aluminum-made oil coolers have core elements provided with coverings of a brazing shet which has been previously applied to the exterior surfaces of the elements. The coverings of the core elements are treated in a vacuum furnace. In detail, after respective parts or members of the conventional aluminum oil cooler have been assembled, the assembled oil cooler is placed in the vacuum furnace so as to melt only the covering. Then the braze covering is solidified in order to fix and bind respective parts to each other. Particular material of the braze covering of a kind to be melted at the temperature lower than that of the core elements by about 5-10 degrees C. is necessary to be selected. And it is necessary to keep the interior temperature of the vacuum furnace at 610-615 degrees C. in order to carry out effective braze welding of respective parts and members. It is noted that, however, both the core elements and the oil cooler casing can not be braze jointed or fixed simultaneously, because radiation heat generated in the vacuum furnace fails to sufficiently distribute or permeate every corners of the parts and members of the oil cooler after the core elements and the casing are assembled. As a result, the braze coverings applied on each part are apt to be melted insufficiently. According to another manufacturing method of the conventional oil cooler, the core elements and the cooler casing are manufactured and braze-treated separately, then the elements are installed in the casing. Consequently, much contacting area is formed between the core elements and casing, so that many sealing members are necessary and the number of parts disadvantageously increases.
3. Summary of the Invention
Accordingly, it is an object of the present invention to provide a novel oil cooler used to engines in which the shortcomings above of the conventional oil coolers are solved.
It is another object of the present invention to provide an oil cooler having few portion to be sealed between the oil passage and cooling water passage and, therefore, few chance of blending the oil and water.
It is still another object to provide a novel oil cooler of a simple structure.
It is still another object to provide a producing method of aluminum-made oil coolers, by which method the core elements and the casing can be assembled in degree as higher as possible before the assembled oil cooler is braze jointed in the vacuum furnace.
The various objects of the present invention are attained by providing the oil cooler provided with the following conditions.
(i) The oil cooler of the present invention has a core placed within a cooler casing and the core is constructed by a plurality of flat and hollow doughnut-like elements 1 and fin members 2 sandwiched between two flat and hollow doughnutlike elements 1. These elements each has a pair of cooling water flowing holes 3 and 4 which are matched or coincided in position with the adjacent holes 3 and 4 of the adjacent element just under or above the former one with the fin member 2 having corresponding holes formed therein being placed on the set of elements. Cooling water flowing holes 3 and 4 of the uppermost or top elements of the core are closed by a closing means 5.
(ii) Each element 1 consists of a pair of metal plates 6 and 6 of a flat doughnut shape and has an inner circumferential wall 8 and an outer circumferential wall 7 of the same height, which walls are formed on the inner circumference and the outer circumference of the metal plate 6. A partition ridge 9 extends diametrically between the inner and the outer circumferential walls 8 and 7 and has the same height as that of these walls. The flowing holes 3 and 4 are placed at both sides of the partition ridge 9 and respectively have hole peripheral or ring-like portions extended or projected outward so as to make flanges 10, 11, 12 and 13 used for braze treatment. A plurality of metal plates 6 are piled up on each other so as to face a concave face of the plate 6 to an opposite or convex surface of other adjacent plate 6 just under or above the former.
(iii) The cooler casing housing the element core 24 consists of a planar doughnut-shaped base 14, a central pipe 15 attached to an inner peripheral edge through its end, and a dish-like member 18 having a central opening 16 to which another end of the central pipe 15 is attached so as to form second oil openings 23 around the circumferential edge of the central opening 16. The dish-like member 18 is attached to the base 14 through its outer pendent edge. A first gap 19 is formed between the inner circumferential edge of the core 24 and the outer wall of the central pipe 15 and a second gap 27 is formed between the outer circumferential edge of the core 24 and the inner wall of the pendent portion of the dish-like member 18. The lower end of the first gap 19 near the base 14 opens and the upper end near the dish-like member 18 closes. Oppositely the lower end of the second gap 27 near the base 14 closes and the upper end adjacent to the dish-like member 18 opens.
(iv) The base 14 has a pair of dents or concavities 21 and 22, respectively formed therein so as to be oppose to the pair of ho.les 3 and 4 of the adjacent element 1. In addition, the base 14 has a pair of cooling water flowing pipes 25 and 26, respectively led to the concavities 21 and 22, which cooling water flowing pipes extend outward from the base 14. The first oil hole 17 is formed in the base 14 so as to be led to the first gap 19.
The last object of the present invention is attained by providing the oil cooler manufacturing method which contains the following conditions.
The method is adapted to manufacture the oil cooler containing a core in its casing according to the present invention. Structural parts of the oil cooler are made of aluminum or its alloy materials and coverings of a brazing material are previously applied to at least one of two structural parts to be adhered to each other. The method has the following structural conditions.
(i) A step in which the dish-like member 18 constituting a part of the oil cooler casing 20 is removed, an assembly of core elements 24 is placed on the base 14 constituting another part of the casing 20, the brazing sheet coverings applied to the elements 1 are melted in the vacuum furnace of a high temperature, and the soft brazing sheet coverings are solidified in order to attach all parts or members including the base 14 integrally.
(ii) Another step by which the outer pendent edge of the dish-like member 18 is welded to the outer circumferential edge of the base 14 of the oil cooler casing 20, and the top portion of the center pipe 15 is welded to the central opening 16 of the dish-like member 18.
(iii) The core 24 is fabricated by piling up a plurality of flat and hollow doughnut-like elements 1, inserting the fin members 2 between two adjacent elements 1, making the cooling water flowing holes 3 and 4 of an element 1 correspond or match to the holes 3 and 4 of the adjacent element 1, and closing the cooling water flowing holes 3 and 4 of the top element 1 by means of the closing means 5.
(iv) Respective elements 1 are made of a pair of flat and doughnut-like metal plates 6 and 6 having the inner circumferential wall 8 and the outer circumferential wall 7 of the same height, respectively formed at the inner circumference and the outer circumference thereof. The pair of cooling water flowing holes 3 and 4 are placed adjacently at both sides of the ridge 9 extending in the diameter or radius direction of the metal plate 6 and having the same height as that of the walls 7 and 8. The flat and ring-like edges are projected outward from these holes 3 and 4 in order to form flanges 10, 11, 12 and 13 used to brazing joint these metal plates 6 to each other in a manner of back-to-back or front-to-front arrangement so as to make respective flowing holes 3 and 4 correspond to adjacent flowing holes 3 and 4.
(v) The oil cooler casing 20 has as described above the flat and doughnut-like base 14, the central pipe 15 attached to the inner circumference of the base 14 through an end thereof and to the central opening 16 through another end thereof. The set of second oil holes 23 are provided around the central opening 16 of the dish-like member 18 to be fixed to the base 14 through its outer circumference. The dish-like member 18 constitutes a part of the oil cooler casing 20. The first gap 19 is formed between the inner circumferential vertical face of the core 24 and the outer wall of the pipe 15 and the second gap 27 is provided between the outer circumferential vertical face of the core 24 and the inner face of the outer circumferential pendent edge 29. The first gap 19 has its opening at the side of the base 14 and another opening at the side of the dish-like member 18 is closed. The end adjacent to the base 14 of the second gap 27 is closed and another end adjacent to the dish-like member 18 opens.
(vi) The base 14 has a pair of concaves 21 and 22 placed so as to face the pair of flowing holes 3 and 4, respectively formed in the element 1 adjacent to the base 14, and also a pair of cooling water pipes 25 and 26, respectively led to these concaves 21 and 22, which pipes project outward from the outer periphery of the base 14. The circumferential edge of the element 1 adjacent to the base 14 or placed just above the base is connected to the circumferential edge of the base 14. In addition the base 14 has a first oil hole 17 shaped as shown.
The objects and other objects, and features and advantages of the present invention will be apparent by reading the following detailed description stating the illustrative example or preferred embodiment with reference to the accompanying drawings.
FIG. 1 shows a section taken along the line I--I of FIG. 2 depicting an oil cooler according to the present invention;
FIG. 2 is a flat view of the oil cooler;
FIG. 3 is a section taken along the line III--III of FIG. 1,
FIG. 4 is a section taken along the line IV--IV of FIG. 1;
FIG. 5 is a perspective and exploded view of the element used in the oil cooler;
FIG. 6 is a section taken along the line VI--VI of FIG. 1;
FIG. 7 is an explanatory view of the oil cooler fabricating method according to the present invention; and
FIG. 8 is vertical section of the oil cooler when it is used with reference to an engine.